Here we have a GREAT demonstration of the difference between polar and non-polar solvents.
Water won't touch sharpie, because water is a polar solvent, and sharpie ink is non-polar.
If you try to dissolve the sharpie with virtually any alcohol, or really, any hydrocarbon (a non-polar solvent) it will come up with varying degrees of effort, depending on how strong a solvent your hydrocarbon is.
Likewise, if you try to dissolve sugar (a polar molecule) with alcohol, or oil or brakleen--a non-polar solvent-- it won't work very well.
But if you try to dissolve the sugar, or sugary spot with a polar solvent such as the water in the energy drink, it will readily dissolve.
You would likely have seen the same effect with alcohol and plain water.